Documents disponibles écrits par cet auteur

Computational fluid dynamics modeling of corrugated static mixers for turbulent applications / Mirella Coroneo in Industrial & engineering chemistry research, Vol. 51 N° 49 (Décembre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 49 (Décembre 2012) . - pp. 15986-15996 Titre : Computational fluid dynamics modeling of corrugated static mixers for turbulent applications Type de document : texte imprimé Auteurs : Mirella Coroneo, Auteur ; Giuseppina Montante, Auteur ; Alessandro Paglianti, Auteur Année de publication : 2013 Article en page(s) : pp. 15986-15996 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Static  mixer  Modeling  Computational  fluid  dynamics Résumé : This work is aimed at investigating the capability of a fully predictive computational fluid dynamics (CFD) approach to catch the main features of the liquid flow in pipelines equipped with corrugated static mixer inserts. The simulations are based on the numerical solution of the Reynolds averaged Navier—Stokes equations on the three-dimensional domain closely representing the static mixer geometry. As a benchmark, literature experiments on a laboratory scale SMV mixer were considered and the simulation results obtained at different locations were compared with relevant velocity and tracer concentration data. The effect of the turbulence modeling, the near-wall treatment, and the numerical approximations on the accuracy of the results is discussed. The results analysis demonstrated that the selected CFD model can be reliably adopted to evaluate the velocity field and the mixing performances of turbulent flows in static mixers for design and optimization purposes. On the other hand, the application of the same model to an industrial scale corrugated plate mixer highlighted the effects of the distributor geometry and of the distance between consecutive elements on the mixing of two miscible liquids. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26732124 [article] Computational fluid dynamics modeling of corrugated static mixers for turbulent applications [texte imprimé] / Mirella Coroneo, Auteur ; Giuseppina Montante, Auteur ; Alessandro Paglianti, Auteur . - 2013 . - pp. 15986-15996. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 49 (Décembre 2012) . - pp. 15986-15996 Mots-clés : Static  mixer  Modeling  Computational  fluid  dynamics Résumé : This work is aimed at investigating the capability of a fully predictive computational fluid dynamics (CFD) approach to catch the main features of the liquid flow in pipelines equipped with corrugated static mixer inserts. The simulations are based on the numerical solution of the Reynolds averaged Navier—Stokes equations on the three-dimensional domain closely representing the static mixer geometry. As a benchmark, literature experiments on a laboratory scale SMV mixer were considered and the simulation results obtained at different locations were compared with relevant velocity and tracer concentration data. The effect of the turbulence modeling, the near-wall treatment, and the numerical approximations on the accuracy of the results is discussed. The results analysis demonstrated that the selected CFD model can be reliably adopted to evaluate the velocity field and the mixing performances of turbulent flows in static mixers for design and optimization purposes. On the other hand, the application of the same model to an industrial scale corrugated plate mixer highlighted the effects of the distributor geometry and of the distance between consecutive elements on the mixing of two miscible liquids. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26732124

Effect of macroinstabilities in single- and multiple-impeller stirred tanks / Alessandro Paglianti in Industrial & engineering chemistry research, Vol. 47 n°14 (Juillet 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4944–4952 Titre : Effect of macroinstabilities in single- and multiple-impeller stirred tanks Type de document : texte imprimé Auteurs : Alessandro Paglianti, Auteur ; Zuohua Liu, Auteur ; Giuseppina Montante, Auteur ; Franco Magelli, Auteur Année de publication : 2008 Article en page(s) : p. 4944–4952 Langues : Anglais (eng) Mots-clés : Macroinstabilities;  Stirred  tanks Résumé : In this work, a simplified analysis of the features of macroinstabilities in stirred tanks is proposed. The experimental part of the study is based on the collection of time series acquired by pressure transducers placed on the tank wall. The measurements are not invasive, because of the probe position, and they can be easily performed in laboratory and in industrial equipment, due to the instrumentation characteristics. With respect to previous investigations, the experimental analysis is extended from Rushton and pitched-blade turbines to Chemineer BT-6 and the effect of multiple impellers (MIs) is considered. The MI presence, frequency, velocity, and strength are obtained from the analysis of the collected pressure time traces; simplified correlations for their prediction are proposed. Finally, the dynamic pressure components associated to the MIs are presented, and a simplified model to assess their importance with respect to those produced by the blade passage frequency is suggested. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800253u [article] Effect of macroinstabilities in single- and multiple-impeller stirred tanks [texte imprimé] / Alessandro Paglianti, Auteur ; Zuohua Liu, Auteur ; Giuseppina Montante, Auteur ; Franco Magelli, Auteur . - 2008 . - p. 4944–4952. Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°14 (Juillet 2008) . - p. 4944–4952 Mots-clés : Macroinstabilities;  Stirred  tanks Résumé : In this work, a simplified analysis of the features of macroinstabilities in stirred tanks is proposed. The experimental part of the study is based on the collection of time series acquired by pressure transducers placed on the tank wall. The measurements are not invasive, because of the probe position, and they can be easily performed in laboratory and in industrial equipment, due to the instrumentation characteristics. With respect to previous investigations, the experimental analysis is extended from Rushton and pitched-blade turbines to Chemineer BT-6 and the effect of multiple impellers (MIs) is considered. The MI presence, frequency, velocity, and strength are obtained from the analysis of the collected pressure time traces; simplified correlations for their prediction are proposed. Finally, the dynamic pressure components associated to the MIs are presented, and a simplified model to assess their importance with respect to those produced by the blade passage frequency is suggested. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800253u

Numerical and experimental fluid - dynamic analysis to improve the mass transfer performances of Pd − Ag membrane modules for hydrogen purification / Mirella Coroneo in Industrial & engineering chemistry research, Vol. 49 N° 19 (Octobre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 19 (Octobre 2010) . - pp. 9300-9309 Titre : Numerical and experimental fluid - dynamic analysis to improve the mass transfer performances of Pd − Ag membrane modules for hydrogen purification Type de document : texte imprimé Auteurs : Mirella Coroneo, Auteur ; Giuseppina Montante, Auteur ; Alessandro Paglianti, Auteur Année de publication : 2010 Article en page(s) : pp. 9300-9309 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Purification  Mass  transfer  Hydrodynamics Résumé : This work is aimed at investigating the impact of the fluid flow features on the behavior of gas separation membrane modules. The investigation is carried out by particle image velocimetry (PIV) experiments and computational fluid dynamics (CFD) simulations. The experimental velocity data collected in a laboratory scale membrane module confirm the reliability of the gas velocity field calculated numerically solving the Navier-Stokes equations by a general-purpose finite volume CFD code, and the effect of the observed nonideal flow distribution on the module separation performances is discussed. Afterward, the case of a pilot scale module equipped with three Pd-Ag membranes, which are well-suited for the separation of H2 from methane steam reforming gas mixtures, is considered. The appropriateness of the selected CFD method for the design and the geometric optimization of membrane modules of pilot size is demonstrated. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23289664 [article] Numerical and experimental fluid - dynamic analysis to improve the mass transfer performances of Pd − Ag membrane modules for hydrogen purification [texte imprimé] / Mirella Coroneo, Auteur ; Giuseppina Montante, Auteur ; Alessandro Paglianti, Auteur . - 2010 . - pp. 9300-9309. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 19 (Octobre 2010) . - pp. 9300-9309 Mots-clés : Purification  Mass  transfer  Hydrodynamics Résumé : This work is aimed at investigating the impact of the fluid flow features on the behavior of gas separation membrane modules. The investigation is carried out by particle image velocimetry (PIV) experiments and computational fluid dynamics (CFD) simulations. The experimental velocity data collected in a laboratory scale membrane module confirm the reliability of the gas velocity field calculated numerically solving the Navier-Stokes equations by a general-purpose finite volume CFD code, and the effect of the observed nonideal flow distribution on the module separation performances is discussed. Afterward, the case of a pilot scale module equipped with three Pd-Ag membranes, which are well-suited for the separation of H2 from methane steam reforming gas mixtures, is considered. The appropriateness of the selected CFD method for the design and the geometric optimization of membrane modules of pilot size is demonstrated. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23289664

Optimization of mechanical agitation and evaluation of the mass-transfer resistance in the oil transesterification reaction for biodiesel production / Dario Frascari in Industrial & engineering chemistry research, Vol. 48 N° 16 (Août 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7540–7549 Titre : Optimization of mechanical agitation and evaluation of the mass-transfer resistance in the oil transesterification reaction for biodiesel production Type de document : texte imprimé Auteurs : Dario Frascari, Auteur ; Michele Zuccaro, Auteur ; Alessandro Paglianti, Auteur Année de publication : 2009 Article en page(s) : pp. 7540–7549 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Sunflower  oil  KOH-catalyzed  transesterification  Mechanical  agitation  Biodiesel  synthesis  reaction Résumé : The KOH-catalyzed transesterification of sunflower oil with methanol was studied in batch conditions in a 22 L stirred reactor in order to (i) develop criteria for the energetic optimization of mechanical agitation in the biodiesel synthesis reaction; (ii) obtain preliminary information on the decantation of the reaction products; (iii) evaluate the influence of the mass-transfer resistance under different mixing conditions. Different combinations of radial, axial, and pitched-blade impellers were tested. For each combination an optimal rotational speed was identified, characterized on the one hand by a drastic reduction of the specific mixing energy, and on the other by a 20−30% increase of reaction time. An evaluation of the reaction and mass-transfer characteristic times showed that the optimized tests are characterized by a not negligible mass-transfer resistance. The complete halt of the agitation after a 1−2 min mixing time led to a further decrease of mixing energy, without any increase of reaction time. Preliminary decantation tests showed that the individuation of an optimized agitation speed for the reaction step, combined with the agitation halt after a short mixing time, has positive effects on the liquid−liquid separation step. The results were compared with those of a twin study conducted with static mixing. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900283j [article] Optimization of mechanical agitation and evaluation of the mass-transfer resistance in the oil transesterification reaction for biodiesel production [texte imprimé] / Dario Frascari, Auteur ; Michele Zuccaro, Auteur ; Alessandro Paglianti, Auteur . - 2009 . - pp. 7540–7549. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 16 (Août 2009) . - pp. 7540–7549 Mots-clés : Sunflower  oil  KOH-catalyzed  transesterification  Mechanical  agitation  Biodiesel  synthesis  reaction Résumé : The KOH-catalyzed transesterification of sunflower oil with methanol was studied in batch conditions in a 22 L stirred reactor in order to (i) develop criteria for the energetic optimization of mechanical agitation in the biodiesel synthesis reaction; (ii) obtain preliminary information on the decantation of the reaction products; (iii) evaluate the influence of the mass-transfer resistance under different mixing conditions. Different combinations of radial, axial, and pitched-blade impellers were tested. For each combination an optimal rotational speed was identified, characterized on the one hand by a drastic reduction of the specific mixing energy, and on the other by a 20−30% increase of reaction time. An evaluation of the reaction and mass-transfer characteristic times showed that the optimized tests are characterized by a not negligible mass-transfer resistance. The complete halt of the agitation after a 1−2 min mixing time led to a further decrease of mixing energy, without any increase of reaction time. Preliminary decantation tests showed that the individuation of an optimized agitation speed for the reaction step, combined with the agitation halt after a short mixing time, has positive effects on the liquid−liquid separation step. The results were compared with those of a twin study conducted with static mixing. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900283j

Two-phase flow and bubble size distribution in air-sparged and surface-aerated vessels stirred by a dual impeller / Giuseppina Montante in Industrial & engineering chemistry research, Vol. 49 N° 6 (Mars 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 6 (Mars 2010) . - pp. 2613–2623 Titre : Two-phase flow and bubble size distribution in air-sparged and surface-aerated vessels stirred by a dual impeller Type de document : texte imprimé Auteurs : Giuseppina Montante, Auteur ; Fabio Laurenzi, Auteur ; Alessandro Paglianti, Auteur Année de publication : 2010 Article en page(s) : pp. 2613–2623 Note générale : Industrial Chemistry Langues : Anglais (eng) Mots-clés : Flow  Bubble  Size  Distribution  Air  Sparged  Surface-Aerated  Vessels  Dual  Impeller Résumé : The aim of this work is to investigate the turbulent hydrodynamic features of a fully baffled gas−liquid stirred vessel equipped with a dual turbine consisting of a radial concave-blade turbine and a downflow pitched blade turbine (PBT). Two different operating modes are analyzed, namely air sparged and surface aerated. A two-phase particle image velocimetry (PIV) technique, based on a single laser sheet source and two cameras, each provided with a filter for separately catching the light scattered by the liquid seeding particles or the bubbles, was adopted for detecting independently and simultaneously the liquid and bubble phase velocities. The mean flow fields of the gas and liquid phases, the rms velocity fluctuation maps of the two phases, and a comparison with the corresponding velocity measurements effected in single-phase conditions are presented. The typical bubble size distribution (BSD) in the two gas−liquid systems obtained by a digital image processing method is also presented, and its dependency on the gas feeding configuration and on the dimensionless Weber number is shown. The effects on the hydrodynamic behavior of the gas−liquid dispersion of liquid viscosity as well as of gas flow rate or impeller speed for the air-sparged and surface-aerated systems, respectively, are discussed. The results suggest that simultaneous detection of the flow fields of the two phases is required for appropriate, detailed evaluation of the system features. Even a limited viscosity change has a significant impact on the system hydrodynamics, since it affects both the flow field and the BSD. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9006276 [article] Two-phase flow and bubble size distribution in air-sparged and surface-aerated vessels stirred by a dual impeller [texte imprimé] / Giuseppina Montante, Auteur ; Fabio Laurenzi, Auteur ; Alessandro Paglianti, Auteur . - 2010 . - pp. 2613–2623. Industrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 6 (Mars 2010) . - pp. 2613–2623 Mots-clés : Flow  Bubble  Size  Distribution  Air  Sparged  Surface-Aerated  Vessels  Dual  Impeller Résumé : The aim of this work is to investigate the turbulent hydrodynamic features of a fully baffled gas−liquid stirred vessel equipped with a dual turbine consisting of a radial concave-blade turbine and a downflow pitched blade turbine (PBT). Two different operating modes are analyzed, namely air sparged and surface aerated. A two-phase particle image velocimetry (PIV) technique, based on a single laser sheet source and two cameras, each provided with a filter for separately catching the light scattered by the liquid seeding particles or the bubbles, was adopted for detecting independently and simultaneously the liquid and bubble phase velocities. The mean flow fields of the gas and liquid phases, the rms velocity fluctuation maps of the two phases, and a comparison with the corresponding velocity measurements effected in single-phase conditions are presented. The typical bubble size distribution (BSD) in the two gas−liquid systems obtained by a digital image processing method is also presented, and its dependency on the gas feeding configuration and on the dimensionless Weber number is shown. The effects on the hydrodynamic behavior of the gas−liquid dispersion of liquid viscosity as well as of gas flow rate or impeller speed for the air-sparged and surface-aerated systems, respectively, are discussed. The results suggest that simultaneous detection of the flow fields of the two phases is required for appropriate, detailed evaluation of the system features. Even a limited viscosity change has a significant impact on the system hydrodynamics, since it affects both the flow field and the BSD. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9006276